Sheet accumulator device for automatic sheet stackers



Dec. 31, 1968 M. D. MARTIN 3,419,266

SHEET ACCUMULATOR DEVICE FOR AUTOMATIC SHEET STACKERS Filed Feb. 20,1967 Sheet of 5 N 3Q 5! l n t "l I I I v fin-J o I ll I I I k s n .H E 33 c Ill Q *3 '1 V \i i INVENTOR Ni MERRILL 0. MART/IV ATITORNEY M. D.MARTIN 3,419,266

' CE- FOR A Sheet IVEN r01? MERE/LL 0. MART/Al AT TORNE Y M. D. MARTINDec. 31, 1968 SHEET ACCUMULATOR DEVICE FOR AUTOMATIC SHEET STACKERSSheet Filed Feb. 20, 1967 IN VE N TOR MERR/LL 0. MA BY AT TORNEY M. D.MARTIN Dec. 31, 1968 SHEET ACCUMULATOR DEVICE- FOR AUTOMATIC SHEETSTACKERS Sheet Filed Feb. 20, 1967 INVENTOR MERE/LL 0. MART/N ATTOIRNEYM. D. MARTIN Dec. 31, 1968 SHEET ACCUMULATOR DEVICE FOR AUTOMATIC SHEETSTACKERS Sheet 5 of Filed Feb. 20, 1967 INVENTOR MERRILL D. MART/NATTORNEY United States Patent 0 3,419,266 SHEET ACCUMULATOR DEVICE FORAUTO- MATIC SHEET STACKERS Merrill D. Martin, 2 Mall Court, Oakland,Calif. 94611 Filed Feb. 20, 1967, Ser. No. 617,400 11 'Claims. (Cl.27186) ABSTRACT OF THE DISCLOSURE In automatic sheet stackers of thetype shown in Patent No. 2,901,250, issued Aug. 25, 1959 to Geo. M.Martin, the sheets are discharged from the end of the conveyor frame,the discharge end of which frame is swung upwardly in a straight line soas to drop the discharged sheets on the top of the stack evenly. In animprovement on that type of machine shown in U.S. Patent No. 3,321,202,issued May 23, 1967, to Merrill D. Martin, there is provided a bracketpivoted at each end of the conveyor frame, and being turned inproportion to the change of angularity of the conveyor frame thereby tomaintain a constant attitude relatively to the ground or to the stack.On each bracket there are also supported adjustable corner guideabutments spaced from the ends the conveyor frame against which thesheet abuts so as to be accurately located with respect to the stack.The improvement of the present application consists of supportingcatcher fingers on a cross frame between and on said brackets so thatthe catcher fingers can be withdrawn into an out of the way positionbeneath the conveyor frame. A system of gears and racks on the supportfor the catcher fingers is operated by pneumatic devices for moving thecatcher fingers simultaneously into position to catch and support thedischarged sheets. There is also pivoted a catcher plate in each guideabutment swingable into and out of position in registry with the levelof the catcher fingers to support the corners of the sheets. The catcherplates are also operated by pneumatic devices, which latter are timedwith the stacker controls for raising and lowering the discharge end ofthe conveyor frame.

Cross reference This patent application is an improvement on theaforesaid U.S. Patent No. 3,321,202.

Brief description of the invention The sheet accumulator is necessary onsheet stackers, particularly of the type wherein the discharge end ofthe accumulator is raised vertically to discharge sheets one by one,thereby to form a stack either on a pallet or on a conveyor. In order topermit time for carrying a stack of sheets away from the discharge endof the conveyor frame without stopping the feeding of the sheets, theaccumulator device of this invention is rendered operative when a stackis completed to catch the sheets from the stacker While the previouslyformed stack is removed; then as the stacker frame is lowered, thecatcher elements are withdrawn from operative position thereby to dropaccumulated sheets onto the pallet or conveyor. The spacing of thecatcher fingers and plates forming the accumulator below the level ofthe discharge end of the conveyor frame in such that the accumulatedstack of sheets does not rise above the level of the conveyor frameduring the interval needed for removing the previously formed stack andthe returning of the conveyor frame to its initial position.

Description of figures in the drawings FIG. 1 is a side view of astacker illustrating relative 3,419,266 Patented Dec. 31, 1968 positionsof the parts and of the accumulator device relatively to the stacker andthe stack of sheets.

FIG. 2 is a fragmental perspective View of the delivery end of thestacker showing the accumulator device in extended position.

FIG. 3 is a fragmental end view of the support and the actuatingmechanism for the catcher fingers.

FIG. 4 is a fragmental plan view of the support and actuating mechanismfor the catcher fingers.

FIG. 5 is a sub-assembly view of one of the guides and supports for oneof the catcher fingers, removed from the supporting base and beingviewed from its base face.

FIG. 6 is a view of one of the guides for a finger without gear and rackdrive.

FIG. 7 is a cross-sectional view of one of the guides with gear and racktaken substantially on line 77 of FIG. 5.

FIG. 8 is a sectional view of said guide taken substantially on line 8-8of FIG. 5.

FIG. 9 is a sectional view of the guide shown in FIG. 6, the sectionbeing taken substantially through the lines 9-9 of FIG. 6.

FIG. 10 is a plan view showing one of the catcher plates and itsoperating mechanism.

FIG. 11 is an edge view of one of the catcher plates and its operatingmechanism mounted on the adjacent sheet aligning element.

FIG. 12 is a diagram illustrating the controls for the accumulator.

Detailed description The improvement herein is preferably used on astacker apparatus shown and described in more detail in said U.S. PatentNo. 3,321,202. In the description of parts of said stacker apparatus,the part numbers used in said last mentioned patent will be used todenote corresponding parts herein referred to. On a base 1 is swingablysupported a conveyor frame 2 partly by an adjustable raising andlowering mechanism 3 connected to about the middle of the conveyor frame2 and by a compensating lever device 4 at the intake end of the conveyorframe 2. Under the delivery end of the stacker frame 2 is either asuitable pallet or a delivery conveyor 6 which is coordinated with theposition of the conveyor frame 2 so that it operates when the conveyorframe 2 is raised to the predetermined height of the stack. An aircushion device 7 is mounted on the delivery end of the conveyor frame 2on adjustable mountings to maintain a constant attitude relatively tothe stack for producing an air cushion on the top of the stack and belowthe sheets delivered from the conveyor frame 2. This air cushion device7 is spaced at -a substantial distance below the level of the deliveryend of the conveyor frame 2. This air cushion device 7 includes amanifold 31 mounted at each end on a pivoted bracket plate 32, whichlatter are journalled on -a conveyor shaft 33 in the delivery end of theconveyor frame 2. This manifold 31 is held generally horizontally orparallel with the top of the stack by the turning of the pivoted bracketplates 32 in conformance with the changing of the angular position ofthe conveyor frame 2 by means of a link 39 pivotally connected to theupper portion of each bracket plate 32 at one end thereof, and to acrank arm 41 extended at an angle from the lever arm of the raising andlowering device 3. For locating the sheets on the stack, angle or cornerguides are formed respectively by an abutment wall 42 and guide wall 43supported adjustably on a cross bar 46 spaced from the delivery end ofthe conveyor frame 2. The cross bar 46 in turn is supported on spacedadjusting bars 48 adjustably mounted on the pivoted bracket plates 32 inthe manner shown in said copending application.

The sheet catching or accumulating device is mounted on the delivery endof the conveyor frame 2.

Sheet catching fingers 101 are mounted at the outer ends thereof on across bar 102 which extends parallel with the delivery end of theconveyor frame 2. The catching fingers 101 are supported and guided inguides 103 mounted on a base plate 104, which latter in turn is suitablymounted on the bottom of the manifold 31. Thus the base plate 104 issupported on the pivoted bracket plates 32 and supports the catcherfingers 101 in a generally horizontal attitude below the level of thedelivery end of the conveyor frame 2.

The set of catcher fingers 10.1 is moved from concealed position beneaththe manifold 31, into extended position beyond the delivery end of theconveyor frame 2, in unison by a gear rack mechanism 105 operated by apiston 106 in a cylinder 107, in this illustration pneumatically.Certain of the spaced guides 103', shown in FIGS. 5 to 8, have a gearshaft 108 fixed therein at right angles perpendicularly to the adjacentcatcher fingers 101. The gear shaft 108 supports a drive gear 109 and alarger diameter shifting gear 110 parallel with the base plate 104. Thedrive gear 109 engages a gear rack 111 formed on a side of an operatingbar 112 movable along the base plate 104, which operating bar 112 inturn is suitably connected to the piston rod 1.13 of the piston 106. Thelarger shifting gear is integral with the drive gear 109 and engages agear rack 114 formed along the adjacent side of the adjacent catcherfinger 101. When the piston 106 is reciprocated in the cylinder 107, itmoves the operating bar 112 and its several gear racks 11.1 therewith,which latter in turn rotate the respective drive gears 109 and shiftinggears 110 thereby to transmit movement to the gear racks 114 and thecatcher fingers 101, for moving the latter into and out of catchingposition respectively. All the guides 103 and .103 have spaced pairs ofrollers 115 between which the respective catcher fingers 101 are guided.

The cylinder 107 is mounted at one end thereof on a travel bracket 116slideable in a groove 117 in the base plate 104 and is supported on ascrew shaft 1.18 threaded through the bracket 116 and journalled in abearing lug 119 on the end of the base plate 104. A handle knob 120 onthe end of the screw shaft 118 facilitates the turning of the screwshaft 118, for adjusting the initial position of the catcher fingers.101.

The catcher plates 121 cooperate with the fingers 101 to support theouter corners of the sheets delivered from the conveyor frame 2. On theoutside of each guide wall 43 is provided a horizontal flange 122.Spaced below the flange 122 is a bearing lug 123 adjacent a horizontalslit 124. Each catcher plate 121 is in the shape of a sector of acircle, on the corner 125 of which is secured a perpendicular shaft 126.The flange 122 has a bearing 127 therethrough in registry with thebearing lug 123, and the shaft 126 extends through said bearing lug 123and through said bearing 127. A crank arm 128 is secured to the top ofthe shaft 126. A pneumatic cylinder 129 is pivotally mounted at one endthereof to the flange 122. A piston 130 Works in the cylinder 129. Thepiston rod 131 of said piston 130 extends through the other closed endof the cylinder 129 and is connected by a. pivot yoke 132 to the crankarm 128. As the double action piston 130 is reciprocated, it rocks theshaft 126, thereby swings the catcher plate 121 into and out of sheetcatching position respectively. The slits 124 and the catcher plates.121 are positioned on the same plane as the catcher fingers 101.

The simultaneous actuation of the catcher fingers 101 and catcher plates121 is accomplished in the manner illustrated in the diagram in FIG. 12.

Each cylinder 107 and 129 has an air hose or flexible conduit 133connected to each end thereof, which are respectively connected toconduits 134. A suitable threeway valve alternately connects theconduits 134 to a supply conduit 136, to operate the cylinders 107 and129 to move the catcher fingers 101 and catcher plates 121 into sheetcatching positions and back into the outof-the-way positionsrespectively. The valve 135 is of suitable spring action whereby springnormally holds the valve 135 in an initial position to admit air underpressure to the closed free ends of the respective cylinders 107 and129, thereby to normally withdraw said catcher fingers .101 and catcherplates 129 into the respective out-ofthe-way positions. When the valve135 is shifted to its alternate position to admit air under pressure tothe pivoted ends of the cylinders 107 and 129, then the respectivepistons are moved to shift the catcher fingers 10-1 and catcher plates129 into extended position below the sheets delivered from the conveyorframe 2. The shifting of the valve 135 from said initial position, inthe herein illustrative diagram is accomplished by a solenoid 137 whichmay be controlled manually by a switch 138.

In the present illustration the solenoid 137 has one of its supply line139 interrupted, in parallel with the switch 138, by a cam switch .141actuated by the cam 154 of the automatic stacker in the circuitdescribed in and shown in FIG. 12 of said U.S. Patent No. 3,321,202,thereby to energize the solenoid when the conveyor frame reaches apredetermined height and hold it energized until the conveyor frame isreturned to its initial position, permitting suificient interval for theremoval of the sheets stacked on the delivery conveyor 6. The spacing ofthe catcher fingers 101 and catcher plates 121 below the level of thedelivery end of the conveyor frame 2 is predetermined to accommodatebelow the level of the delivery end of the conveyor frame 2 all thesheets that may be delivered during said interval needed for the removalof the stack on said pallet or conveyor 6. This spacing of the catcherfingers 101 and plates 121 is predetermined in relation to the speed ofsheet delivery from said delivery end and said needed interval forremoval of the completed stack.

It is to be noted in this embodiment, that the accumulating device ismounted below the air cushion device 7, thereby to interpose the aircushion between the discharged sheets and the fingers .101 and plates121, for cushioning the accumulation. An advantage of so locating theaccumulator device is that the air cushion prevents smearing of printedmatter on the accumulated sheets.

I claim:

1. In a sheet accumulator for sheet stackers, the combination with thesheet delivery part of the sheet stacker and means to raise and lowersaid delivery part to deliver sheets onto a stack, the improvements of:

a plurality of catcher fingers,

guide means to support and guide said fingers in parallel spacedrelation below the level of said delivery part to catch sheets deliveredtherefrom, mounting means to mount said guide means on said deliverypart spaced to a predetermined distance below the level of the sheetdelivery to accommodate a predetermined height of accumulated sheets,

means to move said fingers in unison into and out of sheet catchingposition,

and control means responsive to the angular movement of said deliverypart to actuate said moving means to move said fingers into sheetcatching position after a predetermined height of rising of saiddelivery end thereby to support and stack the sheets, and to withdrawsaid fingers from below said sheets after said delivery end is lowered.

2. The sheet accumulator defined in claim 1, wherein said finger movingmeans includes:

a finger gear rack on the sides of at least two of said fingers,

an operating bar guided across said guide means,

operating gear racks formed on portions of said operating bar adjacentsaid finger gear racks,

gear means coacting with said finger gear racks and said operating gearracks thereby to convert lineal movement of said operating bar intolineal movement of said fingers respectively into and out of sheetcatching position.

3. The sheet accumulator defined in claim 2, and

spaced pairs of spaced rollers in said guide means respectively aboveand below the respective fingers to support and brace said fingers inparallel positions.

4. The sheet accumulator defined in claim 2, and

a transverse member connecting the free ends of said fingers.

5. The sheet accumulator defined in claim 1, wherein said sheet stackerhas abutment and guide elements and means to support said abutment andguide elements spaced from said delivery part so that said elements riseand lower with said delivery part,

catcher plates,

means on said abutment and guide elements to support said catcher platesin generally horizontal position in registry with said fingers tosupport the corners of the sheets accumulated on said fingers betweensaid abutment and guide elements,

and means on said elements for swinging said catcher platessubstantially horizontally into and out of catching position,

6. The sheet accumulator defined in claim 5, said control meansoperating said finger moving means and said catcher plate moving meansin synchronism.

7. The sheet accumulator defined in claim 5, said control means beingactuated by the movement of said stacker from an initial position tooperate said finger moving means and said catcher plate moving means tomove said fingers and plates into catching position in synchronism aftera predetermined stacking movement of said delivery part of said stacker,and to Withdraw said fingers and plates into inoperative position uponthe return of said delivery part into said initial position.

8. In a sheet accumulator the combination with a conveyor frame having adelivery end and means to raise and lower said conveyor framerespectively from and to an initial position so as to move the deliveryend of said conveyor frame in a substantially perpendicular plane forstacking sheets conveyed to and discharged from said delivery end, of

catcher means spaced below said delivery end for accumulating sheetsthereon,

self-adjustable support means actuated by the swinging of said frame tocompensate for change of angular position of said conveyor frame duringthe raising and lowering of said delivery end thereby to maintain saidcatcher means in a generally horizontal attitude below said deliveryend,

means to move said catcher means into and out of catching position,

and control means responsive to the angular movement of said conveyorframe to actuate said catcher moving means thereby to move said catchermeans into operative position after a predetermined height of rising ofsaid delivery end and to withdraw said catching means into inoperativeposition after said delivery end is returned into said initial position.

9. The sheet accumulator defined in claim 8, wherein the spacing of saidcatcher means below the level of the delivery end of said conveyor frameis so related to the speed of sheet feeding from said delivery end as toaccommodate all the sheets delivered during said period between saidpredetermined height and said return of the conveyor frame to initialposition.

'10. The invention defined in claim 9 and said catcher means including:

first catcher elements movable outwardly beyond the delivery end,

and other catcher elements spaced outwardly from said delivery end andmovable inwardly toward said delivery end in registry with said firstcatcher elements.

11. The invention defined in claim 8 wherein an air cushion producingdevice is provided on the conveyor frame beneath said delivery end, andsaid catcher means being mounted under said air cushion producing deviceto interpose an air cushion between the discharged sheets and catcherdevice.

References Cited UNITED STATES PATENTS 6/1919 Steele. 3/1959 Thrasher.

US. Cl. X.R. 2l46

